Combination of a chamber and a piston, a pump, a motor, a shock absorber and a transducer incorporating the combination

ABSTRACT

A piston-chamber combination comprising an elongate chamber which is bounded by an inner chamber wall and comprising an elastically deformable piston comprising a container in said chamber to be sealingly movable relative to said chamber at least between first and second longitudinal positions of said chamber, said chamber having cross-sections of different cross-sectional areas at the first and second longitudinal positions of said chamber and at least substantially continuously different cross-sectional areas at intermediate longitudinal positions between the first and second longitudinal positions thereof, the cross-sectional area at the first longitudinal position being larger than the cross-sections area at the second longitudinal position, said piston including a piston body and sealing means supported by the piston body being designed to adapt itself and said sealing means to said different cross-sectional areas of said chamber during the relative movements of said pistion from the second longitudinal position through said intermediate longitudinal positions to the first longitudinal position of said chamber.

TECHNICAL FIELD

A piston-chamber combination comprising an elongate chamber which isbounded by an inner chamber wall, and comprising a piston in saidchamber to be sealingly movable relative to said chamber wall at leastbetween a first longitudinal position and a second longitudinalpositions of the chamber, said chamber having cross-sections ofdifferent cross-sectional areas and different circumferential lengths atthe first and second longitudinal positions and at least substantiallycontinuously different cross-sectional areas and differentcircumferential length at intermediate longitudinal positions betweenthe first and second longitudinal positions, the cross-sectional areaand circumferential length at said second longitudinal position beingsmaller than the cross-sectional area and circumferential length at saidfirst longitudinal position, said piston comprising a container which iselastically deformable thereby providing for different cross-sectionalareas and circumferential lengths of the piston adaptating the same tosaid different cross-sectional areas and different circumferentiallengths of the chamber during the relative movements of the pistonbetween the first and second longitudinal positions through saidintermediate longitudinal positions of the chamber.

Inflation valves are the Dunlop-Woods valve, the Sclaverand valve andthe Schrader valve. These are in use for inflation of closed chambers,e.g. tyres of vehicles. The last two mentioned valve types have aspring-force operated valve core pin, and may be opened by depressingthis pin for inflation and deflation of the chamber. Depressing thevalve core pin may be done by manual activation, by a pressure of afluid or by a valve actuator. The first two mentioned valve types may beopened by the pressure of a fluid alone, while the last mentioned onebest may be opened by a valve actuator, as otherwise a high pressure maybe needed to depress the pin.

BACKGROUND OF THE INVENTION

This invention deals with solutions for the problem of obtaining afriction force low enough to at least avoid jamming between a piston,specifically a piston comprising a container having an elasticallydeformable container wall, and the wall of an elongate chamber duringthe stroke, the chamber having different sizes of cross-sectional area'sin its longitudinal direction, specifically those having differentcircumferential length's, when the piston is sealingly movable relativeto said chamber.

A problem with embodiments of FIGS. 6, 8 and 9-12 (incl.) of WO 00/70227may be that the piston may jam in the smaller cross-sections of thechamber having cross-sections with different circumferential sizes.Jamming may occur due to high frictional forces of the material of thewall of the pistons. These forces may mainly be created by thecompression of the material(s) of the wall of the piston when the pistonis moving from a first longitudinal position in the chamber having thebiggest cross-sectional area to a second longitudinal position where thecross-sectional area and the circumferential size is smaller. FIGS. 1-3(incl.) of the current patent application show examples of highfrictional forces for non-moving pistons comprising a container in anon-moving chamber with or without internal pressure in the chamber.This results in high contact pressures between the piston and the wallof the chamber: jamming may occur.

A further problem may be that embodiments of pistons comprising acontainer of WO 00/70227 may leak their fluid, and thus may change theirsealing capability. As in the solutions of the earlier mentioned problemfor pistons comprising a container with an elastically deformable wallthe sealing force is created by internal pressure, leakage may be animportant problem.

OBJECT OF THE INVENTION

The object is to provide combinations of a piston and a chamber whichmay sealingly move when the chambers have different cross-sectionalareas when the circumferences of these cross-sections are different.

SUMMARY OF THE INVENTION

In the first aspect, the invention relates to a combination of a pistonand a chamber, wherein:

-   -   the the piston is produced to have a production size of the        container in the stress-free and undeformed state thereof in        which the circumferential length of the piston is approximately        equivalent to the circumferential length of said chamber at said        second longitudinal position, the container being expandable        from its production size in a direction transversally with        respect to the longitudinal direction of the chamber thereby        providing for an expansion of the piston from the production        size thereof during the relative movements of the piston from        said second longitudinal position to said first longitudinal        position.

In the present context, the cross-sections are preferably takenperpendicularly to the longitudinal axis (=transversal direction).

Preferably, the second cross-sectional area is 95-15%, such as 95-70% ofthe first cross-sectional area. In certain situations, the secondcross-sectional area is approximately 50% of the first cross-sectionalarea.

A number of different technologies may be used in order to realise thiscombination. These technologies are described further in relation to thesubsequent aspects of the invention.

One such technology is one wherein the piston comprises an elasticallydeformable container comprising a deformable material.

In that situation, the deformable material may be a fluid or a mixtureof fluids, such as water, steam, and/or gas, or a foam. This material,or a part thereof, may be compressible, such as gas or a mixture ofwater and gas, or it may be at least substantially incompressible.

This may be achieved by choosing the production size (stress free,undeformed) of the piston approximately equivalent to thecircumferential length of the smallest cross-sectional area of across-section of the chamber, and to expand it when moving to alongitudinal position with a bigger

And this may be achieved by providing means to keep a certain sealingforce from the piston on the wall of the chamber: by keeping theinternal pressure of the piston on (a) certain predetermined level(s),which may be kept constant during the stroke. A pressure level of acertain size depends on the difference in circumferential length of thecross sections, and on the possibility to get a suitable sealing at thecross section with the smallest circumferential length. If thedifference is big, and the appropriate pressure level too high to obtaina suitable sealing force at the smallest circumferential length, thanchange of the pressure may be arranged during the stroke. This calls fora pressure management of the piston. As commercially used materials arenormally not tight, specifically when quite high pressures may be used,there must be a possibility to keep this pressure, e.g. by using a valvefor inflation purposes.

When the cross-sectional area of the chamber changes, the volume of thecontainer may change. Thus, in a cross-section through the longitudinaldirection of the chamber the container may have a first shape at thefirst longitudinal direction and a second shape at the secondlongitudinal direction, the first shape may be different from the secondshape. In one situation, at least part when the deformable material iscompressible and the first shape has an area being larger than an areaof the second shape. In that situation, the overall volume of thecontainer changes, whereby the fluid should be compressible.Alternatively or optionally, the piston may comprise an enclosed spacecommunicating with the deformable container, said enclosed space havinga variable volume. In that manner, that the enclosed space may take upor release fluid when the deformable container changes volume. Thechange of the volume of the container is by that automaticallyadjustable. It may result in that the pressure in the container remainsconstant during the stroke.

Also, the enclosed space may comprise a spring-biased piston. Thisspring may define the pressure in the piston when changing its volume.

The volume of the enclosed space may be varied. In that manner, theoverall pressure or maximum/minimum pressure of the container may bealtered.

When the enclosed space is updivided into a first and a second enclosedspace, the spaces further comprising means for defining the volume ofthe first enclosed space so that the pressure of fluid in the firstenclosed space may relate to the pressure in the second enclosed space.The last mentioned space may be inflatable e.g. by means of a valve,preferably an inflation valve, such as a Schrader valve.

The defining means may be adapted to define the pressure in the firstenclosed space at least substantially constant during the stroke.

However, any kind of pressure level may be defined by the definingmeans: e.g. a pressure raise may be necessary when the container expandsto such a big cross-sectional area at the first longitudinal positionthat the contact area at the present pressure value may become toolittle, in order to maintain a suitable sealing. The defining means maybe a pair of pistons, one in each enclosed space. The second enclosedspace may be inflated to a certain pressure level, so that a pressureraise may be communicated to the first enclosed space, despite the factthat the volume of the second enclosed space may become bigger as well.This may be achieved by e.g. a combination of a piston and a chamberwith different cross-sectional area's in the piston rod, which iscomprised in the second enclosed space. A pressure drop may also bedesignable.

Pressure management of the piston may also be achieved by relating thepressure of fluid in the enclosed space with the pressure of fluid inthe chamber. By providing means for defining the volume of the enclosedspace communicating with the chamber. In this manner, the pressure ofthe deformable container may be varied in order to obtain a suitablesealing. For example, a simple manner would be to have the definingmeans adapted to define the pressure in the enclosed space to raise whenthe container is moving from the second longitudinal position to thefirst longitudinal position. In this situation, a simple piston betweenthe two enclosed spaces may be provided (in order to not loose any ofthe fluid in the deformable container).

In fact, the use of this piston may define any relation between thepressures in that the chamber in which the piston translates may taperin the same manner as the main chamber of the combination.

The container may be inflated by a pressure source inside the piston, oran external pressure source, like one outside the combination and/orwhen the chamber is the source itself. All solutions demand a valvecommunicating with the piston. This valve may preferably an inflationvalve, best a Schrader valve. This valve type has a spring biased valvecore pin and closes independant of the pressure in the piston, and allkinds of fluids may flow through it. It may however also be anothervalve type, e.g. a check valve.

The container may be inflated through an enclosed space where thespring-biased tuning piston operates as a check valve. The fluid mayflow through longitudinal ducts in the bearing of the piston rod of thespring biased piston, from a pressure source.

When the enclosed space is divided up into a first and second enclosedspace, the inflation may be done with the chamber as the pressuresource, as the second enclosed space may prohibit inflation through itto the first enclosed space. The chamber may have an inlet valve in thefoot of the chamber. For inflation of the container an inflation valve,e.g. a Schrader valve may be used, together with an actuator. This maybe an activating pin according to WO 96/10903 or WO 97/43570, or a valveactuator according to WO99/26002. The core pin of the valve is movingtowards the chamber when closing.

When the working pressure in the chamber is higher than the pressure inthe piston, the piston may be inflated automatically.

When the working pressure in the chamber is lower than the pressure inthe piston than it is necessary to obtain a higher pressure by e.g.temporary closing the outlet valve in the foot of the chamber. When thevalve is a Schrader valve which may be opened by means of a valveactuator according to WO 99/26002, this may be achieved by creating abypass in the form of a channel by connecting the chamber and the spacebetween the valve actuator and the core pin of the valve. This bypassmay be openened (the Schrader valve may remain closed) and closed (theSchrader valve may open) and may be accomplished by e.g. a movablepiston. The movement of this piston may be arranged manually e.g. by apedal, which is turning around an axle from an inactive position to anactive position and vice versa by an operator. It may also be achievedby other means like an actuator, initiated by the result of a pressuremeasurement in the chamber and/or the container.

Obtaining the predetermined pressure in the container may be achievedmanually—the operator being informed by a manometer which is measuringthe pressure in the container. It may also be achieved automatically,e.g. by a release valve in the container. It may also be achieved by aspring-force operated cap which closes the channel above the valveactuator when the pressure exceeds a certain predetermined pressurevalue. Another solution is that of a comparable solution of the closablebypass of the outlet valve of the chamber—a pressure measurement may benecessary in the container, which may steer an actuator which is openingand closing the bypass of the valve actuator according to WO 99/26002 ofa Schrader valve of the container at a predetermined pressure value.

The above mentioned solutions are applicable too to any pistonscomprising a container, incl. those shown in WO 00/65235 and WO00/70227.

In order to reduce the longitudinal stretching of the piston comprisinga container when subjected to the pressure of the chamber, and to allowthe expansion in the transversal direction, the container may comprisean elastically deformable material comprising reinforcement means, suchas a textile, fibre or other reinforcement means, preferably positionedin the wall of the container. The piston comprising a container may alsocomprise reinforcement means which are not positioned in the wall, e.g.a plurality of elastic arms, which may or may not be inflatable,connected to the wall of the container. When inflatable, thereinforcement functions also to limit the deformation of the wall of thecontainer due to the pressure in the chamber.

Another aspect of the invention is one relating to a combination of apiston and a chamber, wherein: the chamber defines an elongate chamberhaving a longitudinal axis,

-   -   the piston being movable in the chamber from a second        longitudinal position to a first longitudinal position,    -   the chamber having an elastically deformable inner wall along at        least part of the inner chamber wall between the first and        second longitudinal positions,    -   the chamber having, at a first longitudinal position thereof        when the piston is positioned at that position, a first        cross-sectional area thereof and, at a second longitudinal        position thereof when the piston is positioned at that position,        a second cross-sectional area, the first cross-sectional area        being larger than the second cross-sectional area, the change in        cross-section of the chamber being at least substantially        continuous between the first and second longitudinal positions        when the piston is moved between the first and second        longitudinal positions.

Thus, alternatively to the combinations where the piston adapts to thecross-sectional changes of the chamber, this aspect relates to a chamberhaving adapting capabilities.

Naturally, the piston may be made of an at least substantiallyincompressible material—or a combination may be made of the adaptingchamber and an adapting piston—such as a piston according to the aboveaspects.

Preferably, the piston has, in a cross section along the longitudinalaxis, a shape tapering in a direction from the first longitudinalposition to the second longitudinal position.

A preferred manner of providing an adapting chamber is to have thechamber comprise:

-   -   an outer supporting structure enclosing the inner wall and    -   a fluid held by a space defined by the outer supporting        structure and the inner wall.        In that manner, the choice of fluid or a combination of fluids        may help defining the properties of the chamber, such as the        sealing between the wall and the piston as well as the force        required etc.

It is clear that depending on from where the combination is seen, one ofthe piston and the chamber may be stationary and the other moving—orboth may be moving. This has no impact on the functioning of thecombination.

The piston may also slide over an internal and an external wall. Theinternal wall may have a taper form, while the external wall iscylindrical.

Naturally, the present combination may be used for a number of purposesin that it primarily focuses on a novel manner of providing anadditional manner of tailoring translation of a piston to the forcerequired/taken up. In fact, the area/shape of the cross-section may bevaried along the length of the chamber in order to adapt the combinationfor specific purposes and/or forces. One purpose is to provide a pumpfor use by women or teenagers—a pump that nevertheless should be able toprovide a certain pressure. In that situation, an ergonomically improvedpump may be required by determining the force which the person mayprovide at which position of the piston—and thereby provide a chamberwith a suitable cross-sectional area/shape.

Another use of the combination would be for a shock absorber where thearea/shape would determine what translation a certain shock (force)would require. Also, an actuator may be provided where the amount offluid introduced into the chamber will provide differing translation ofthe piston depending on the actual position of the piston prior to theintroducing of the fluid.

In fact, the nature of the piston, the relative positions of the firstand the second longitudinal positions and the arrangement of any valvesconnected to the chamber may provide pumps, motors, actuators, shockabsorbers etc. with different pressure characteristics and differentforce characteristics.

The preferred embodiments of the combination of a chamber and a pistonhave been described as examples to be used in piston pumps. This howevershould not limit the coverage of this invention to the said application,as it may be mainly the valve arrangement of the chamber besides thefact which item or medium may initiate the movement, which may bedescisive for the type of application: pump, actuator, shock absorber ormotor. In a piston pump a medium may be sucted into a chamber which maythereafter be closed by a valve arrangement. The medium may becompressed by the movement of the chamber and/or the piston andthereafter a valve may release this compressed medium from the chamber.In an actuator a medium may be pressed into a chamber by a valvearrangement and the piston and/or the chamber may be moving, initiatingthe movement of an attached device. In shock absorbers the chamber maybe completely closed, wherein a compressable medium may be compressed bythe movement of the chamber and/or the piston. In the case anon-compressable medium may be positioned inside the chamber, e.g. thepiston may be equipeed by several small channels which may give adynamic friction, so that the movement may be slowed down.

Further the invention may also be used in propulsion applications wherea medium may be used to move a piston and/or a chamber, which may turnaround an axis as e.g. in a motor. The principles according thisinvention may be applicable on all above mentioned applications. Theprinciples of the invention may also be used in other pneumatic and/orhydraulic applications than the above mentioned piston pumps.

The various embodiments described above are provided by way ofillustration only and should not be construed to limit the invention.Those skilled in the art will readily recognize various modifications,changes, and combinations of elements which may be made to the presentinvention without strictly following the exemplary embodiments andapplications illustrated and described herein, and without departingfrom the true spirit and scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, preferred embodiments of the invention will bedescribed with reference to the drawings wherein:

FIG. 1A shows a longitudinal cross-section of a non-moving piston in anon-pressurized cylinder at the first longitudinal position—the pistonis shown in its production size, and when pressurized.

FIG. 1B shows the contact pressure of the pressurized piston of FIG. 1Aon the wall of the cylinder.

FIG. 2A shows a longitudinal cross-section of the piston of FIG. 1A in acylinder at the first (right) and second (left) longitudinal position,the piston is non-pressurized.

FIG. 2B shows the contact pressure of the piston of FIG. 2A on the wallof the cylinder at the second longitudinal position.

FIG. 2C shows a longitudinal cross-section of the piston of FIG. 1A in acylinder at the second longitudinal position, the piston is pressurizedon the same pressure level as the one of FIG. 1A—also is shown thepiston at the first longitudinal position (production) size.

FIG. 2D shows the contact pressure of the piston of FIG. 2C on the wallof the cylinder at the second longitudinal position.

FIG. 3A shows a longitudinal cross-section of a piston of FIG. 1A in acylinder at the first longitudinal position shown in its productionsize, and pressurized while the piston is subjected to a pressure in thechamber.

FIG. 3B shows the contact pressure of the piston of FIG. 3A on the wallof the cylinder.

FIG. 4A shows a longitudinal cross-section of a non-moving pistonaccording to the invention in a non-pressurized cylinder at the secondlongitudinal position, shown in its production size, and whenpressurized to a certain level.

FIG. 4B shows the contact pressure of the piston of FIG. 4A on the wallof the cylinder.

FIG. 4C shows a longitudinal cross-section of a non-moving pistonaccording to the invention in a cylinder at the second longitudinalposition, shown in its production size, and at the first longitudinalposition when pressurized to the same level as that of FIG. 4A.

FIG. 4D shows the contact pressure of the piston of FIG. 4C on the wallof the cylinder.

FIG. 5A shows a longitudinal cross-section of the piston of FIG. 4A in anon-pressurized cylinder at the second longitudinal position, the pistonwith its production size, and when pressurized.

FIG. 5B shows the contact pressure of the pressurized piston of FIG. 5Aon the wall of the cylinder.

FIG. 5C shows a longitudinal cross-section of the piston of FIG. 4A in acylinder at the second longitudinal position, the piston with itsproduction size, and when pressurized, subjected to a pressure from thecylinder.

FIG. 5D shows the contact pressure of the piston of FIG. 5C on the wallof the cylinder.

FIG. 6A shows a longitudinal cross-section of a chamber with fixeddifferent areas of the transversal cross-sections and a first embodimentof the piston comprising a textile reinforcement with radially-axiallychanging dimensions during the stroke—the piston arrangement is shown atthe beginning, and at the end of a stroke—pressurized—where it hasunpressurized its production size.

FIG. 6B shows an enlargement of the piston of FIG. 6A at the beginningof a stroke.

FIG. 6C shows an enlargement of the piston of FIG. 6A at the end of astroke.

FIG. 7A shows a longitudinal cross-section of a chamber with fixeddifferent areas of the transversal cross-sections and a secondembodiment of the piston comprising a fiber reinforcement (‘TrellisEffect’) with radially-axially changing dimensions of the elasticmaterial of the wall during the stroke—the piston arrangement is shownat the beginning, and at the end of a stroke—pressurized—where it hasunpressurized its production size.

FIG. 7B shows an enlargement of the piston of FIG. 7A at the beginningof a stroke.

FIG. 7C shows an enlargement of the piston of FIG. 7A at the end of astroke.

FIG. 8A shows a longitudinal cross-section of a chamber with fixeddifferent areas of the transversal cross-sections and a third embodimentof the piston comprising a fiber reinforcement (no ‘Trellis Effect’)with radially-axially changing dimensions during the stroke—the pistonarrangement is shown at the beginning, and at the end of a stroke whereit has its production size.

FIG. 8B shows an enlargement of the piston of FIG. 8A at the beginningof a stroke.

FIG. 8C shows an enlargement of the piston of FIG. 8A at the end of astroke.

FIG. 8D shows a top view of the piston of FIG. 8A with a reinforcementin the wall in planes through the central axis of the piston—left: atthe first longitudinal position, right: at the second longitudinalposition.

FIG. 8E shows a top view of the piston of FIG. 8A having reinforcementsin the skin in planes partly through the central axis and partly outsidethe central axis—left: at the first longitudinal position, right: at thesecond longitudinal position.

FIG. 9A shows a longitudinal cross-section of a chamber with fixeddifferent areas of the transversal cross-sections and a fourthembodiment of the piston comprising an “octopus” device, limitingstretching of the container wall by tentacles, which may beinflatable—the piston arrangement is shown at the beginning, and at theend of a stroke where it has its production size.

FIG. 9B shows an enlargement of the piston of FIG. 9A at the beginningof a stroke.

FIG. 9C shows an enlargement of the piston of FIG. 9A at the end of astroke.

FIG. 10A shows the embodiment of FIG. 6 where the pressure inside thepiston may be changend by inflation through e.g. a Schrader valve whichis positioned in the handle and/or e.g. a check valve in the piston rod,and where an enclosed space is balancing the change in volume of thepiston during the stroke.

FIG. 10B shows instead of an inflation valve, a bushing enablingconnection to an external pressure source.

FIG. 10C shows details of the guidance of the rod of the check valve.

FIG. 10D shows the flexable piston of the check valve in the piston rod.

FIG. 11A shows the embodiment of FIG. 6 where the pressure inside thepiston may be maintained constant during the stroke and where a secondenclosed space may be inflated through a Schrader valve which ispositioned in the handle, communicating with the first enclosed spacethrough a piston arrangement—the piston may be inflated by a Schradervalve+ valve actuator arrangement with the pressure of the chamber aspressure source, while the outlet valve of the chamber may be manuallycontrolled by a turnable pedal.

FIG. 11B shows a piston arrangement and its bearing where the pistonarrangement is communicating between the second and the first enclosedspace.

FIG. 11C shows a alternative piston arrangement adapting itself to thechanging cross-sectional area's in its longitudinal direction inside thepiston rod.

FIG. 11D shows an enlargement of the inflation arrangement of the pistonof FIG. 11A at the end of the stroke.

FIG. 11E shows an enlargment of the bypass arrangement for the valveactuator for closing and opening of the outlet valve.

FIG. 11F shows an enlargement of an automatic closing and openingarrangement of the outlet valve—a comparable system is shown foroptaining a predetermined pressure value in the piston (dashed).

FIG. 11G shows an enlargement of an inflation arrangement of the pistonof FIG. 11A, comprising a combination of a valve actuator and a springforce operated cap, which makes it possible to automatically inflate thepiston from the chamber to a certain predetermined pressure.

FIG. 12 shows an arrangement where the pressure in the container maydepend of the pressure in the chamber.

FIG. 13A shows a longitudinal cross-section of a chamber with a flexiblewall having different areas of the transversal cross-sections and apiston with fixed geometrical sizes—the arrangement of the combinationis shown at the beginning and at the end of the pump stroke.

FIG. 13B shows an enlargement of the arrangement of the combination atthe beginning of a pump stroke.

FIG. 13C shows an enlargement of the arrangement of the combinationduring a pump stroke.

FIG. 13D shows an enlargement of the arrangement of the combination atthe end of a pump stroke.

FIG. 14 shows a longitudinal cross-section of a chamber having aflexible wall with different areas of the transversal cross-sections anda piston with variable geometrical sizes—the arrangement of thecombination is shown at the beginning, during a pump stroke and at theend of the stroke.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1A shows the longitudinal cross-section of a non-movingnon-pressurized piston 5 at the first longitudinal position of anon-pressurized chamber 1, having at that position a circularcross-sections with a constant radius. The piston 5 may have aproduction size approximately the diameter of the chamber 1 at thisfirst longitudinal position. The piston 5* when pressurized to a certainpressure level is shown. The pressure inside the piston 5* results in acertain contact length.

FIG. 1B shows the contact pressure of the piston 5* of FIG. 1A. Thepiston 5* may jam at this longitudinal position.

FIG. 2A shows the longitudinal cross-section of a non-movingnon-pressurized piston 5 at the first longitudinal position and thepiston 5′ at the second longitudinal position of a non-pressurizedchamber 1, the chamber having circular cross-sections with a constantradius at both the first and second longitudinal positions. The piston 5may have a production size approximately the diameter of the chamber 1at this first longitudinal position. The piston 5′ shows the piston 5,non-pressurized positioned into the smaller cross-section of the secondlongitudinal position.

FIG. 2B shows the contact pressure of the piston 5′ on the wall of thechamber at the second longitudinal position. The piston 5′ may jam atthis longitudinal position.

FIG. 2C shows the longitudinal cross-section of a non-movingnon-pressurized piston 5 at the first longitudinal position and thepiston 5′ at the second position of a non-pressurized chamber 1, thechamber having circular cross-sections with a constant radius at boththe first and second longitudinal positions. The piston 5 may have aproduction size approximately the diameter of the chamber 1 at thisfirst longitudinal position. The piston 5′* shows the piston 5,pressurized to the same level as the one of FIG. 1A, positioned into thesmaller cross-section of the second longitudinal position.

FIG. 2D shows the contact pressure of the piston 5′* on the wall of thechamber at the second longitudinal position. The piston 5′* may jam atthis longitudinal position: the friction force may be 72 kg.

FIG. 3A shows the piston 5 of FIG. 1A, and the deformed piston 5″* whenpressurized to the same pressure level of that of piston 5* of FIG. 1A.The deformation is caused by the pressure in the chamber 1*, when thepiston may not have means to limit the stretching, which is mainly inthe meridian (longitudinal direction of the chamber) direction.

FIG. 3B shows the contact pressure. The piston 5″* may jam at thislongitudinal position.

FIG. 4A shows the longitudinal cross-section of a piston 15 at thesecond longitudinal position of a non-pressurized chamber 10, having acircular cross-section. The piston 15 may have a production sizeapproximately the diameter of the chamber 10 at this second longitudinalposition. Piston 15′* shows the deformed piston 15 pressurized to acertain level. The deformation is due to the fact that the Young'smodulus in the hoop direction (in a cross-sectional plane of thechamber) is choosen lower than that in the meridian direction (in thelongitudinal direction of the chamber).

FIG. 4B shows the contact pressure on the wall of piston 15′*. Thisresults in an appropriate friction force (4.2 kg), and suitable sealing.

FIG. 4C shows the longitudinal cross-section of piston 15 at the secondlongitudinal position (production size) of the non-pressurized chamber10, and when pressurized 15″* at the first longitudinal position—thepiston 15″* may have the same pressure as when the piston 15′* ispositioned at the second longitudinal position of the chamber 10 (FIG.4A). Also here is the deformation in the hoop—and meridian directiondifferent.

FIG. 4D shows the contact pressure on the wall of piston 15″*. Thisresults in an appropriate friction force (0.7 kg) and a suitablesealing.

Therefore, it is possible to sealingly move a piston comprising anelastically deformable container from a smaller to a biggercross-sectional area while having the same internal pressure—within thelimitations for the diameters of the cross-sections which were chosen inthis experiment.

FIG. 5A shows the longitudinal cross-section of the piston 15(production size) and the piston 15′* at the second longitudinalposition of the non-pressurized chamber 10. The piston 15′* is showingthe deformed structure of piston 15 when the piston 15 is pressurized.The piston 15, 15′* have been attached at the lower end to an imaginarypiston rod in order to prevent piston movement during application of thechamber pressure.

FIG. 5B shows the contact pressure of the piston 15′* of FIG. 5A. Thisis low enough to allow movement (friction force 4.2 kg) and suitable forsealing.

FIG. 5C shows the longitudinal cross-section of the piston 15(production size) and 15″* pressurized and deformed by the chamberpressure at the second longitudinal position of the pressurized chamber10*. The piston 15, 15′* have been attached at the lower end to animaginary piston rod in order to prevent piston movement during theapplication of the chamber pressure. The deformed piston 15″* isapproximately twice as long as the undeformed piston 15.

FIG. 5D shows the contact pressure of the piston 15″* of FIG. 5C. Thisis low enough to allow movement (friction force 3.2 kg) and suitable forsealing.

Therefore, when applying a chamber pressure on a piston comprising apressurized elastically deformable container, it is possible tosealingly move as well, at least at the longitudinal position with thesmallest cross-sectional area. The stretching due to the applied chamberforce is big and it may be necessary to limit this.

FIGS. 6-8 deal with the limitation of the stretching of the wall of thepiston. This comprises a limitation of the stretching in thelongitudinal direction when the piston is subjected to a pressure in thechamber, and to allow expansion in the transversal direction, whenmoving from the second to the first longitudinal position.

The stretching in the longitudinal direction of the wall of thecontainer-type piston may be limited by several methods. It may be doneby a reinforcement of the wall of the container by using e.g. textileand/or fiber reinforcement. It may also be done by an inside the chamberof the container positioned expanding body with a limitation for itsexpansion, while it is connected to the wall of the container. Othermethods may be used, e.g. pressure management of a chamber in-betweentwo walls of the container, pressure management of the space above thecontainer etc.

The expansion behaviour of the wall of the container may be depending onthe type of the stretching limitation used. Moreover, the keeping of thepiston which is moving over the piston rod, while expanding, may beguided by a mechanical stop. The positioning of such a stop may bedepending on the use of the piston-chamber combination. This may also bethe case for the guidance of the container over the piston rod, whileexpanding and/or sujected to external forces.

All kinds of fluids may be used—a combination of a compressable and anon-compressable medium, a compressable medium only or anon-compressable medium only.

As the change of the size of the container may be substantial from thesmallest cross-sectional area, where it has its production size, andexpanded at the biggest cross-sectional area, a communication of thechamber in the container with a first enclosed space, e.g. in the pistonrod may be necessary. In order to keep the pressure in the chamber, thefirst enclosed space may be pressurized as well, also during the changeof the volume of the chamber of the container. Pressure management forat least the first enclosed space may be needed.

FIG. 6A shows a longitudinal cross-section of the chamber 186 with aconcave wall 185 and an inflatable piston comprising a container 208 atthe beginning (=first longitudinal position in the chamber 186) and thesame 208′ at the end of a stroke (=second longitudinal position in thechamber 186). Central axis of the chamber 186 is 184. The container 208′shows its production size, having a textile reinforced 189 in the skin188 of the wall 187. During the stroke, the wall 187 of the containerexpands until a stop arrangement, which may be the textile reinforcement189 and/or a mechanical stop 196 outside the container 208 and/oranother stop arrangement stops the movement during the stroke. And thusthe expansion of the container 208. Depending on the pressure in thechamber 186, there still may occur a longitudinal stretching of the wallof the container, due to pressure in the chamber 186. The main functionhowever of the reinforcement is to limit this longitudinal stretching ofthe wall 187 of the container 208. During the stroke the pressure insidethe container 208,208′ may remain constant. This pressure depends on thechange in the volume of the container 208,208′, thus on the change inthe circumferential length of the cross-sections of the chamber 186during the stroke. It may also be possible that the pressure changesduring the stroke. It may also be possible that the pressure changesduring the stroke, depending or not of the pressure in the chamber 186.

FIG. 6B shows a first embodiment of the expanded piston 208 at thebeginning of a stroke. The wall 187 of the container is build up by askin 188 of a flexable material, which may be e.g. a rubber type or thelike, with a textile reinforcement 189, which allows expansion. Thedirection of the textile reinforcement in relation to the central axis184 (=braid angle) is different from 54°44′. The change of the size ofthe piston during the stroke results not necessarily in an identicalshape, as drawn. Due to the expansion the thickness of the wall of thecontainer may be smaller than that of the container as produced whenpositioned attend of the stroke (=second longitudinal position). Animpervious layer 190 inside the wall 187 may be present. It is tightlysqueezed (193) in the cap 191 in the top and the cap 192 in the bottomof the container 208,208′. Details of said caps are not shown and allkinds of assembling methods may be used—these may be capable to adaptthemselves to the changing thickness of the wall of the container. Bothcaps 191,192 can translate and/or rotate over the piston rod 195. Thesemovements may be done by various methods as e.g. different types ofbearings which are not shown. The cap 191 in the top of the containermay move upwards and downwards. The stop 196 on the piston rod 195outside the container 208 limits the upwards movement of the container208. The cap 192 in the bottom may only move downwards because the stop197 prevent a movement upwards—this embodiment may be thought to be usedin a piston chamber device which has pressure in chamber 186 beneath thepiston. Other arrangements of stops may be possible in other pump types,such as double working pumps, vacuum pumps etc. and depends solely ofthe design specifications. Other arrangements for enabling and/orlimiting the relative movement of the piston to the piston rod mayoccur. The tuning of the sealing force may comprise a combination of anincompressable fluid 205 and a compressable fluid 206 (both alone arealso a possibility) inside the container, while the chamber 209 of thecontainer may communicate with a second enclosed space 210 comprising aspring-force operated piston 126 inside the piston rod 195. The fluid(s)may freely flow through the wall 207 of the piston rod through the hole201. It may be possible that the second enclosed space is communicatingwith a third chamber (see FIG. 11A, while the pressure inside thecontainer also may be depending on the pressure in the chamber 186. Thecontainer may be inflatable through the piston rod 195 and/or bycommunicating with the chamber 186. O-rings or the like 202, 203 in saidcap in the top and in said cap in the bottom, respectively seal the caps191,192 to the piston rod. The cap 204, shown as a screwed assembly atthe end of the piston rod 195 thighthens said piston rod. Comparablestops may be positioned elsewhere on the piston rod, depending on thedemanded movement of the wall of the container. The contact area betweenthe wall of the container and the wall of the chamber is 198.

FIG. 6C shows the piston of FIG. 6B at the end of a pump stroke, whereit has its production size. The cap 191 in the top is moved over adistance a′°from the stop 196. The spring-force operated valve piston126 has been moved over a distance b′. The bottom cap 192 is shownadjacent to the stop 197—when there is pressure in the chamber 186, thenthe bottom cap 192 is pressed against the stop 197. The compressablefluid 206′°and the non-compressable fluid 205′. The contact area198′°between the container 208′°and the wall of the chamber at thesecond longitudinal position.

FIG. 7A shows a longitudinal cross-section of the chamber 186 with aconcave wall 185 and an inflatable piston comprising a container 217 atthe first longitudinal position of the chamber and the same 217′°at thesecond longitudinal position. The container 217′°shows its productionsize, having a fiber reinforced 219 in the skin 216 of the wall 218according to the ‘Trellis Effect’. During the stroke, the wail 218 ofthe container expands until a stop arrangement, which may be the fiberreinforcement 219 and/or a mechanical stop 214 inside the containerand/or another stop arrangement stops the movement during the stroke.And thus stops the expansion of the wall 218 of the container 217. Themain function of the fiber reinforcement is to limit the longitudinalstretching of the wall 218 of the container 217. During the stroke thepressure inside the container 217,217′°may remain constant. Thispressure depends on the change in the volume of the container 217,217′,thus on the change in the circumferential length of the cross-sectionsof the chamber 186 during the stroke. It may also be possible that thepressure changes during the stroke, depending or not of the pressure inthe chamber 186. The contact area 211 between the container 217 and thewall of the chamber at the first longitudinal position. The TrellisEffect is where a decrease of the transverse sectional area of thechamber causes a decrease in the size of the inflatable body(—chamber)in that direction and a three dimensional reduction is possible due tothe fiber architecture, where fibres are shearing layer wiseindependently from each other. See U.S. Pat. No. 6,978,711.

FIG. 7B shows a second embodiment of the expanded piston 217 at thebeginning of a stroke. The wall 218 of the container is build up by askin 216 of a flexible material, which may be e.g. a rubber type or thelike, with a fiber reinforcement 219, which allows expansion of thecontainer wall 218, and thus the direction of the fibers in relation tothe central axis 184 (=braid angle) may be different from 54°44′. Due tothe expansion the thickness of the wall of the container may be smaller,but not necessarily very different than that of the container asproduced when positioned at the end of the stroke (=second longitudinalposition). An impervious layer 190 inside the wall 218 may be present.It is tightly squeezed in the cap 191 in the top and the cap 192 in thebottom of the container 217,217′. Details of said caps are not shown andall kinds of assembling methods may be used—these may be capable toadapt themselves to the changing thickness of the wall of the container.Both caps 191,192 can translate and/or rotate over the piston rod 195.These movements may be done by various methods as e.g. different typesof bearings which are not shown. The cap 191 in the top can move upwardsand downwards until stop 214 limits this movement. The cap 192 in thebottom can only move downwards because the stop 197 prevent a movementupwards—this embodiment is thought to be used in a piston chamber devicewhich has pressure in chamber 186. Other arrangements of stops may bepossible in other pump types, such as double working pumps, vacuum pumpsetc. and depends solely of the design specifications. Other arrangementsfor enabling and/or limiting the relative movement of the piston to thepiston rod may occur. The tuning of the sealing force may comprise acombination of an incompressable fluid 205 and a compressable fluid 206(both alone are also a possibility) inside the container, while thechamber 215 of the container 217,217′may communicate with a secondenclosed space 210 comprising a spring-force operated piston 126 insidethe piston rod 195. The fluid(s) may freely flow through the wall 207 ofthe piston rod through the hole 201. It may be possible that the secondenclosed space 210 is communicating with a third chamber (see FIG. 10),while the pressure inside the container also may be depending on thepressure in the chamber 186. The container may be inflatable through thepiston rod 195 and/or by communicating with the chamber 186. O-rings orthe like 202, 203 in said cap in the top and in said cap in the bottom,respectively seal the caps 191,192 to the piston rod. The cap 204, shownas a screwed assembly at the end of the piston rod 195 thighthens saidpiston rod.

FIG. 7C shows the piston of FIG. 7B at the end of a pump stroke, whereit has its production size. The cap 191 is moved over a distance c′ fromthe stop 216. The spring-force operated valve piston 126 has been movedover a distance d′. The bottom cap 192 is shown adjacent to the stop197—if there is pressure in the chamber 186, than the 192 is pressedagainst the stop 197. The compressable fluid 206′ and thenon-compressable fluid 205′.

FIGS. 8A,B,C show an inflatable piston comprising a container 228 at thebeginning and 228′ at the end of a stroke. The production size is thatof piston 228′ at the second longitudinal position in the chamber 186.The construction of the piston may be identical with that of FIGS.7A,B,C with the exception that the reinforcement comprises of any kindof reinforcement means which may be bendable, and which may ly in apattern of reinforcement ‘colums’ which do not cross each other. Thispattern may be one of parallel to the central axis 184 of the chamber186 or one of where a part of the reinforcement means may be in a planethrough the central axis 184.

FIG. 8B shows the wall 221 with the skin 222 and 224. The reinforcementmeans 227. The contact area 225 between the container 228 and the wallof the chamber at the first longitudinal position.

FIG. 8C shows the contact area 225′between the container 228′°and thewall of the chamber at the second longitudinal position.

FIG. 8D shows a top view of the piston 228 and 228′, respectively withthe reinforcement means 227, and 227′°respectively.

FIG. 8E shows a top view of the piston 228 and 228′, respectively withthe reinforcement means 229, and 229′ respectively.

FIG. 9A shows a longitudinal cross-section of the chamber with aconvex/concave wall 185 and an inflatable piston comprising a container258 at the beginning and the same 258′°at the end of a stroke. Thecontainer 258′ shows its production size.

FIG. 9B shows the longitudinal cross-section of the piston 258 having areinforced skin by a plurality of at least elastically deformablesupport members 254 rotatably fastened to a common member 255, connectedto the an skin 252 of said piston 258,258′. These members are intension, and depending on the hardness of the material, they have acertain maximum stretching length. This limited length limits thestretching of the skin 252 of said piston. The common member 255 mayslide with sliding means 256 over the piston rod 195. For the rest isthe construction comparable with that of the piston 208,208′. Thecontact area is 253.

FIG. 9C shows the longitudinal cross-section of the piston 258′. Thecontact area is 253′.

FIGS. 10-12 deal with the management of the pressure within thecontainer. Pressure management for the piston comprising an inflatablecontainer with an elastically deformable wall is an important part ofthe piston-chamber construction. Pressure management has to do withmaintaining the pressure in the container, in order to keep the sealingon the appropriate level. This means during each stroke where the volumeof the container changes. And in the long term, when leakage from thecontainer may reduce the pressure in the container, which may effect thesealing capability. A flow of fluid may be the solution. To and from thecontainer when it changes volume during a stroke, and/or to thecontainer as such (inflation).

The change in the volume of the container may be balanced with a changein the volume of a first enclosed space, communicating with thecontainer through e.g. a hole in the piston rod. The pressure may alsobe balanced, and this may be done by a spring force operated pistonwhich may be positioned in the first enclosed space. The spring forcemay be originated by a spring or a pressurized enclosed space, e.g. asecond enclosed space, which communicates with the first enclosed spaceby a pair of pistons. Any kind of force transfer may be arranged by eachof the pistons, e.g. by a combination of the second enclosed space and apiston herein, so that the force on the piston in the first enclosedspace remains equal, while the force on the piston in the secondenclosed space reduces, when the pair of pistons moves more into thefirst enclosed space e.g. when fluid is moving from the first enclosedspace into the container. This complies well with p.V=constant in thesecond enclosed space. The tuning of the pressure in the chamber of thecontainer during the entire or a part of the stroke may also be done bya communication of the chamber and the chamber of the container. Thishas already been described in WO00/65235 and WO00/70227.

The container may be inflated through a valve in the piston and/or thehandle. This valve may be a check valve or an inflation valve, e.g. aSchrader valve. The container may be inflated through a valve whichcommunicates with the chamber. If an inflation valve is used, a Schradervalve is preferable because of its security to avoid leakages and itsability to allow to control all kinds of fluids. In order to enableinflation, a valve actuator may be necessary, e.g. the one disclosed inWO99/26002. This valve actuator has the advantage that inflation may beenabled by a very low force—thus very practical in case of manualinflation.

Having a valve communicating with the chamber, it may enable automaticinflation of the container, when the pressure in the container is lowerthan the pressure in the chamber. When this may not be the case, suchhigher pressure in the chamber may be created temporarily by closing theoutlet valve of the chamber near the second longitudinal position of thecontainer in the chamber. This closing and opening may be done manually,e.g. by a pedal, which opens a channel which communicates with a spacebetween the valve actuator (WO99/26002) and e.g. a Schrader valve. Whenopen, the valve actuator may move, but lacks the force to depress thecore pin of the valve and hence the Schrader valve may not open—thus thechamber may be closed, and any high pressure may be build up forenabling inflation of the container. When the channel is closed, theactuator functions as disclosed in WO99/26002. The operator may checkthe pressure in the container by a manometer. Opening and closing ofthis outlet valve may also be done automatically. This may be done byall kinds of means, which initiate the closing of the outlet by a signalof any kind as a result of a measurement of pressure being lower than apredetermined value.

The automatic inflation of the container to a certain pre-determinedvalue may be done by a combination of a valve communicating with thechamber and e.g. a release valve in the container. It releases at acertain predetermined value of the pressure, e.g. to the space above thecontainer or to the chamber. Another option may be that the valveactuator of WO99/26002 may be open firstly after a pre-determined valueof the pressure has been reached, e.g. by combining it with a spring.Another option may be that the opening to the valve actuator is closedwhen the pressure reaches a value over the pre-determined one, by e.g. aspring force operated piston.

FIG. 10A shows a piston-chamber system with a piston comprising acontainer 208,208′ and a chamber 188 having a central axis 184 accordingto FIG. 6A-C. The inflation and pressure management described here mayalso be used for other pistons comprising a container. The container208,208′ may be inflated through a valve 241 in the handle 240 and/or avalve 242 in the piston rod 195. If no handle is used, but e.g. arotating axle, it could be hollow, communicating with e.g. a Schradervalve. The valve 241 may be an inflation valve, e.g. a Schrader valve,comprising a bushing 244 and a valve core 245. The valve in the pistonrod 195 may be a check valve, having a flexible piston 126. The chamberbetween the check valve 242 and the chamber 209 of the container208,208′°was earlier described as the ‘second’ enclosed space 210. Themanometer 250 enables control of the pressure inside the container—nofurther details are shown. It may also be possible to use this manometerto control the pressure in the chamber 186. It may also be possible thatthe chamber 209 of the container 208,208′ has a release-valve (notdrawn) which may be adjusted to a certain pre-determined value of thepressure. The released fluid may be released to the chamber 209 and/orto the space 251.

FIG. 10B shows an alternative option for the inflation valve 241.Instead of the inflation valve 241 in the handle 240, only a bushing 244without a valve core 245 may be present, which enables connection to apressure source.

FIG. 10C shows details of the bearing 246 of the rod 247 of the piston126 which may act as a check valve. The bearing 246 compriseslongitudinal ducts 249 enabling passage of fluid around the rod 247. Thespring 380 enables a pressure on the fluid in the second enclosed space210. The stop 239.

FIG. 10D shows details of the flexible piston 126, which may function ascheck valve 242. The spring 380 keeps the pressure on the piston 126.

FIG. 11A shows a piston-chamber system with a piston comprising acontainer 208,208′ and a chamber 186 having a central axis 184 accordingto FIG. 6A-C. The inflation and pressure management described here mayalso be used for other pistons comprising a container. The container248,248′ may be inflated through a valve communicating with the chamber186. This valve 242 may be a piston 126 according to FIG. 10A,D or itmay be an inflation valve, preferably a Schrader valve 260. The secondclosed space 210 is communicating with the chamber 209 in the containerby a hole 201, while the second enclosed space 210 is communicatingthrough a piston arrangement with a second enclosed space 243, which maybe inflated through e.g. an inflation valve like a Schrader valve 241which may positioned in the handle 240. The valve has a core pin 245. Ifno handle is used, but e.g. a rotating axle, it may be hollow and aSchrader valve may communicate with this channel (not drawn). TheSchrader valve 260 has a valve actuator 261 according to WO99/26002. Thefoot 262 of the chamber 186 may have an outlet valve 263, e.g. aSchrader valve, which may be equipped with another valve actuator 261according to WO99/26002. In order to manually control the outlet valve263, the foot 262 may be equipped with a pedal 265 which can turn anangle a around an axle 264 on the foot 262. The pedal 265 is connectedto a piston rod 267 by an axle 266 in a non-circular hole 275 in the topof the pedal 265. The foot 262 has an inlet valve 269 (not drawn) forthe chamber 186. The (schematically drawn) spring 276 keeps the pedal265 in its initial position 277, where the outlet valve is kept open.The activated position 277′ of the pedal 265 when the outlet valve iskept dosed. The outlet channel 268.

FIG. 11B shows a detail of the communication by a pair of pistons 126(from FIG. 10D) and 270 between the second endosed space 210 and thethird enclosed space 243. The piston rod 271 of the pair of pistons isguided by a bearing 246. The longitudinal ducts 249 in the bearing 246enable the transport of fluid from the spaces between the bearing 246and the pistons 126 and 270. The spring 380 may be present. The pistonrod of the piston type container 248,248′ is 195, with the wall 194.

FIG. 11C shows an alternative wall 273 of the piston rod 272 of thepiston type container 248,248′ which has a angle β°with the central axis184 of the chamber 186. The piston 274 is schematically drawn, and canadapt itself to the changing cross-sectional area's of the inside thepiston rod 272.

FIG. 11D shows piston 248′ on which a housing 280 is build. The housingcomprises a Schrader valve 260, with a core pin 245. The valve actuator261 shown as depressing the core pin 245, while fluid may enter thevalve 260 through channels 286, 287,288 and 289. When the core pin 245is not depressed, the piston ring 279 may seal the wall 285 of the innercylinder 283. The inner cylinder 283 may be sealingly enclosed bysealings 281 and 284 between the housing 280 and the cylinder 282. Thechamber is 186.

FIG. 11E shows the construction of the outlet valve 263 with a core pin245, which is shown depressed by the valve actuator 261. Fluid may flowthrough channels 304, 305, 306 and 307 to the openened valve. The innercylinder 302 is sealingly enclosed between the housing 301 and thecylinder 303 by sealings 281 and 284. A channel 297 having a centralaxis 296 is positioned through the wall of the inner cylinder 302, thewall of the cylinder 303 and the wall of the housing 301. At the outsideof the housing 301 has the opening 308 of channel 297 a widening 309which enables a piston 292 to seal in a closing position 292′ by a top294. The piston 292 may be moving in another channel 295 which may havethe same central axis 296 as channel 297. The bearing 293 for the pistonrod 267 of the piston 292. The piston rod 267 may be connected to thepedal 265 (FIG. 11A) or to other actuators (schematically shown in FIG.11E).

FIG. 11F shows the piston 248′ and the inflation arrangement 368 of FIG.11D, besides the arrangement 369 to control the outlet valve of FIG.11E. The inflation arrangement 368 comprises now also the arrangement370 to control the valve of FIG. 11E. This may be done to enabling theclosing of the valve, when the predetermined pressure has been reached,and opening it when the pressure is lower than the predetermined value.A signal 360 is handled in a converter 361 which gives a signal 362 toan actuator 363, which is actuating through actuating means 364 thepiston 292.

When the chamber has a lower working pressure than the pre-determinedvalue of the pressure in the piston, the arrangement 369 to control theclosing and opening of the outlet valve 263 may be controlled by anotheractuator 363 through means 367 initiated by a signal 365 from theconverter 361. A measurement in the chamber, giving a signal 371 to theconverter 361 and/or 366 may automatically detect whether or not theactual pressure of the chamber is lower than the working pressure of thepiston. This may be specifically practical when the pressure of thepiston is lower than the pre-determined pressure.

FIG. 11G shows schematically a cab 312, 312′ with a spring 310 connectedto the housing 311 of the valve actuator 261. The spring 310 maydetermine the maximum value of the pressure to depress the valve corepin 245, of a Schrader valve 260.

FIG. 12 shows en enlonged piston rod 320 in which a pair of pistons321,322 are positioned at the end of a piston rod 323, which may move ina beating 324. The enclosed space 325.

FIGS. 13A,B,C show the combination of a pump with a pressurizing chamberwith elastically deformable wall with different areas of the transversalcross sections and a piston with a fixed geometrical shape. Within ahousing as e.g. cylinder with fixed geometrical sizes an inflatabelchamber is positioned which is inflatable by a fluid (a non-compressableand/or a compressable fluid). It is also possible that said housing maybe avoided. The inflatable wall comprising e.g. a liner-fiber-covercomposite or also added an impervious skin. The angle of the sealingsurface of the piston is a bit bigger than the comparative angle of thewall of the chamber in relation to an axis parallel to the movement.This difference between said angles and the fact that the momentaneousdeformations of the wall by the piston takes place a bit delayed (byhaving e.g. a viscose non-compressable fluid in the wall of the chamberand/or the right tuning of load regulating means, which may be similarto those which have been shown for the pistons) provides a sealing edge,of which its distance to the central axis of the chamber during themovement between two piston and/or chamber positions may vary. Thisprovides a cross-sectional area change during a stroke, and by that, adesignable operation force. The cross-section of the piston in thedirection of the movement however may also be equal, or with a negativeangle in relation to the angle of the wall of the chamber—in these casesthe ‘nose’ of the piston may be rounded of. In the last mentioned casesit may be more difficult to provide a changing cross-sectional area, andby that, a designable operation force. The wall of the chamber may beequiped with all the already shown loading regulating means the oneshowed on FIG. 12B, and if necessary with the shape regulating means.The velocity of the piston in the chamber may have an effect on thesealing.

FIG. 13A shows piston 230,230′°at four positions of the piston in achamber 231 with a central axis 236. Around an inflatable wall 238 ahousing 234 with fixed geometrical sizes. Within said housing 234 acompressable fluid 232 and a non-compressable fluid 233. There may be avalve arrangement for inflation of the wall (not shown). The shape ofthe piston at the non-pressurized side is only an example to show theprinciple of the sealing edge. The difference in distance between thesealing edge and the central axis 236 at the end and that at thebeginning of the stroke in the shown transversal cross-section isapproximately 39%. The shape of the longitudinal cross-section may bedifferent from the one shown.

FIG. 13B shows the piston after the beginning of a stroke. The distancefrom the sealing edge 235 and the central axis 236 is z,. The angle abetween the piston sealing edge 235 and the central axis 236 of thechamber. The angle v between the wall of the chamber and the centralaxis 236. The angle v is shown smaller than the angle ξ. The sealingedge 235 arranges that the angle v becomes as big as the angle ξ.

FIG. 13B shows the piston after the beginning of a stroke. The distancefrom the sealing edge 235 and the central axis 236 is z₁. The angle ξbetween the piston sealing edge 235 and the central axis 236 of thechamber. The angle v between the wall of the chamber and the centralaxis 236. The angle v is shown smaller than the angle ξ. The sealingedge 235 arranges that the angle v becomes as big as the angle ξ. Otherembodiments of the piston are not shown.

FIG. 13C shows the piston during a stroke. The distance from the sealingedge 235 and the central axis 236 is z₂—this distance is smaller thanz₁.

FIG. 13D shows the piston almost at the end of stroke. The distance fromthe sealing edge 235 and the central axis 236 is z₃—this distance issmaller than z₂.

FIG. 14 shows a combination of a wall of the chamber and the pistonwhich have changeable geometrical shapes, which adapt to each otherduring the pump stroke, enabling a continuous sealing. It has itsproduction size at the second longitudinal position of the chamber.Shown is the chamber of FIG. 13A now with only a non-compressable medium237 and piston 450 at the beginning of a stroke, while the piston 450′is shown just before the end of a stroke. Also all other embodiments ofthe piston which may change dimensions may be used here too. The rightchoice of velocity of the piston and the viscosity of the medium 237 mayhave a positive effect on operations. The longitudinal cross-sectionalshape of the chamber shown in FIG. 14 may also be different.

1. A piston-chamber combination comprising an elongate chamber which isbounded by an inner chamber wall, and comprising a piston in saidchamber to be sealingly movable relative to said chamber wall at leastbetween a first longitudinal position and a second longitudinal positionof the chamber, said chamber having cross-sections of differentcross-sectional areas and different circumferential lengths at the firstand second longitudinal positions, and at least substantiallycontinuously different cross-sectional areas and circumferential lengthsat intermediate longitudinal positions between the first and secondlongitudinal positions, the cross-sectional area and circumferentiallength at said second longitudinal position being smaller than thecross-sectional area and circumferential length at said firstlongitudinal position, said piston comprising a container which iselastically deformable thereby providing for different cross-sectionalareas and circumferential lengths of the piston adapting the same tosaid different cross-sectional areas and different circumferentiallengths of the chamber during the relative movements of the pistonbetween the first and second longitudinal positions through saidintermediate longitudinal positions of the chamber, wherein the pistonis produced to have a production-size of the container in thestress-free and undeformed state thereof in which the circumferentiallength of the piston is approximately equivalent to the circumferentiallength of said chamber at said second longitudinal position, thecontainer being expandable from its production size in a directiontransversely with respect to the longitudinal direction of the chamberthereby providing for an expansion of the piston from the productionsize thereof during the relative movements of the piston from saidsecond longitudinal position to said first longitudinal position, andwherein the container contains a deformable material, the deformablematerial being a fluid or a foam.
 2. A combination according to claim 1,wherein the foam or fluid is adapted to provide, within the container, apressure higher than the highest pressure of the surrounding atmosphereduring translation of the piston from the second longitudinal positionof the chamber to the first longitudinal position thereof or vice versa.3. A piston-chamber combination comprising an elongate chamber which isbounded by an inner chamber wall, and comprising a piston in saidchamber to be sealingly movable relative to said chamber wall at leastbetween a first longitudinal position and a second longitudinal positionof the chamber, said chamber having cross-sections of differentcross-sectional areas and different circumferential lengths at the firstand second longitudinal positions, and at least substantiallycontinuously different cross-sectional areas and circumferential lengthsat intermediate longitudinal positions between the first and secondlongitudinal positions, the cross-sectional area and circumferentiallength at said second longitudinal position being smaller than thecross-sectional area and circumferential length at said firstlongitudinal position, said piston comprising a container which iselastically deformable thereby providing for different cross-sectionalareas and circumferential lengths of the piston adapting the same tosaid different cross-sectional areas and different circumferentiallengths of the chamber during the relative movements of the pistonbetween the first and second longitudinal positions through saidintermediate longitudinal positions of the chamber, wherein the pistonis produced to have a production-size of the container in thestress-free and undeformed state thereof in which the circumferentiallength of the piston is approximately equivalent to the circumferentiallength of said chamber at said second longitudinal position, thecontainer being expandable from its production size in a directiontransversely with respect to the longitudinal direction of the chamberthereby providing for an expansion of the piston from the productionsize thereof during the relative movements of the piston from saidsecond longitudinal position to said first longitudinal position, andwherein, the container contains a deformable material and in across-section through the longitudinal direction, the container, whenbeing positioned at the first longitudinal position of the chamber, hasa first shape which is different from a second shape of the containerwhen being positioned at the second longitudinal position of saidchamber.
 4. A combination according to claim 3, wherein at least part ofthe deformable material is compressible and wherein the first shape hasan area being larger than an area of the second shape.
 5. A combinationaccording to claim 3, wherein the deformable material is at leastsubstantially incompressible.
 6. A piston-chamber combination comprisingan elongate chamber which is bounded by an inner chamber wall, andcomprising a piston in said chamber to be sealingly movable relative tosaid chamber wall at least between a first longitudinal position and asecond longitudinal position of the chamber, said chamber havingcross-sections of different cross-sectional areas and differentcircumferential lengths at the first and second longitudinal positions,and at least substantially continuously different cross-sectional areasand circumferential lengths at intermediate longitudinal positionsbetween the first and second longitudinal positions, the cross-sectionalarea and circumferential length at said second longitudinal positionbeing smaller than the cross-sectional area and circumferential lengthat said first longitudinal position, said piston comprising a containerwhich is elastically deformable thereby providing for differentcross-sectional areas and circumferential lengths of the piston adaptingthe same to said different cross-sectional areas and differentcircumferential lengths of the chamber during the relative movements ofthe piston between the first and second longitudinal positions throughsaid intermediate longitudinal positions of the chamber, wherein thepiston is produced to have a production-size of the container in thestress-free and undeformed state thereof in which the circumferentiallength of the piston is approximately equivalent to the circumferentiallength of said chamber at said second longitudinal position, thecontainer being expandable from its production size in a directiontransversely with respect to the longitudinal direction of the chamberthereby providing for an expansion of the piston from the productionsize thereof during the relative movements of the piston from saidsecond longitudinal position to said first longitudinal position, andwherein the container contains a deformable material and is inflatable,to a certain pre-determined pressure value.
 7. A combination accordingto claim 6, wherein the pressure remains constant during the stroke. 8.A piston-chamber combination comprising an elongate chamber which isbounded by an inner chamber wall, and comprising a piston in saidchamber to be sealingly movable relative to said chamber wall at leastbetween a first longitudinal position and a second longitudinal positionof the chamber, said chamber having cross-sections of differentcross-sectional areas and different circumferential lengths at the firstand second longitudinal positions, and at least substantiallycontinuously different cross-sectional areas and circumferential lengthsat intermediate longitudinal positions between the first and secondlongitudinal positions, the cross-sectional area and circumferentiallength at said second longitudinal position being smaller than thecross-sectional area and circumferential length at said firstlongitudinal position, said piston comprising a container which iselastically deformable thereby providing for different cross-sectionalareas and circumferential lengths of the piston adapting the same tosaid different cross-sectional areas and different circumferentiallengths of the chamber during the relative movements of the pistonbetween the first and second longitudinal positions through saidintermediate longitudinal positions of the chamber, wherein the pistonis produced to have a production-size of the container in thestress-free and undeformed state thereof in which the circumferentiallength of the piston is approximately equivalent to the circumferentiallength of said chamber at said second longitudinal position, thecontainer being expandable from its production size in a directiontransversely with respect to the longitudinal direction of the chamberthereby providing for an expansion of the piston from the productionsize thereof during the relative movements of the piston from saidsecond longitudinal position to said first longitudinal position, thepiston comprising an enclosed space communicating with the deformablecontainer, the enclosed space having a variable volume, the containercontaining a deformable material and the combination further comprisingmeans for defining the volume of the enclosed space so that the pressureof fluid in the enclosed space relates to the pressure in a furtherenclosed space.
 9. A combination according to claim 8, wherein thedefining means are adapted to define the pressure in the enclosed spaceduring the stroke.
 10. A combination according to claim 8, wherein thedefining means are adapted to define the pressure in the enclosed spaceat least substantially constant during the stroke.
 11. A piston-chambercombination comprising an elongate chamber which is bounded by an innerchamber wall, and comprising a piston in said chamber to be sealinglymovable relative to said chamber wall at least between a firstlongitudinal position and a second longitudinal position of the chamber,said chamber having cross-sections of different cross-sectional areasand different circumferential lengths at the first and secondlongitudinal positions, and at least substantially continuouslydifferent cross-sectional areas and circumferential lengths atintermediate longitudinal positions between the first and secondlongitudinal positions, the cross-sectional area and circumferentiallength at said second longitudinal position being smaller than thecross-sectional area and circumferential length at said firstlongitudinal position, said piston comprising a container which iselastically deformable thereby providing for different cross-sectionalareas and circumferential lengths of the piston adapting the same tosaid different cross-sectional areas and different circumferentiallengths of the chamber during the relative movements of the pistonbetween the first and second longitudinal positions through saidintermediate longitudinal positions of the chamber, wherein the pistonis produced to have a production-size of the container in thestress-free and undeformed state thereof in which the circumferentiallength of the piston is approximately equivalent to the circumferentiallength of said chamber at said second longitudinal position, thecontainer being expandable from its production size in a directiontransversely with respect to the longitudinal direction of the chamberthereby providing for an expansion of the piston from the productionsize thereof during the relative movements of the piston from saidsecond longitudinal position to said first longitudinal position, thepiston comprising an enclosed space communicating with the deformablecontainer, the enclosed space having a variable volume, the containercontaining a deformable material and the enclosed space comprising aspring-biased pressure tuning piston, the spring-biased pressure tuningpiston including a check valve through which fluid of an externalpressure source can flow into the enclosed space.
 12. A combinationaccording to claim 11, wherein the fluid from an external pressuresource can enter the enclosed space through an inflation valve,preferably a valve with a core pin biased by a spring, such as aSchrader valve from an external pressure source.
 13. A piston-chambercombination comprising an elongate chamber which is bounded by an innerchamber wall, and comprising a piston in said chamber to be sealinglymovable relative to said chamber wall at least between a firstlongitudinal position and a second longitudinal position of the chamber,said chamber having cross-sections of different cross-sectional areasand different circumferential lengths at the first and secondlongitudinal positions, and at least substantially continuouslydifferent cross-sectional areas and circumferential lengths atintermediate longitudinal positions between the first and secondlongitudinal positions, the cross-sectional area and circumferentiallength at said second longitudinal position being smaller than thecross-sectional area and circumferential length at said firstlongitudinal position, said piston comprising a container defining anenclosed space, the container being elastically deformable therebyproviding for different cross-sectional areas and circumferentiallengths of the piston adapting the same to said differentcross-sectional areas and different circumferential lengths of thechamber during the relative movements of the piston between the firstand second longitudinal positions through said intermediate longitudinalpositions of the chamber, wherein the piston is produced to have aproduction-size of the container in the stress-free and undeformed statethereof in which the circumferential length of the piston isapproximately equivalent to the circumferential length of said chamberat said second longitudinal position, the container being expandablefrom its production size in a direction transversely with respect to thelongitudinal direction of the chamber thereby providing for an expansionof the piston from the production size thereof during the relativemovements of the piston from said second longitudinal position to saidfirst longitudinal position wherein the piston includes at least onevalve and wherein the valve is an inflation valve with a core pin biasedby a spring.
 14. A piston-chamber combination comprising an elongatechamber which is bounded by an inner chamber wall, and comprising apiston in said chamber to be sealingly movable relative to said chamberwall at least between a first longitudinal position and a secondlongitudinal position of the chamber, said chamber having cross-sectionsof different cross-sectional areas and different circumferential lengthsat the first and second longitudinal positions, and at leastsubstantially continuously different cross-sectional areas andcircumferential lengths at intermediate longitudinal positions betweenthe first and second longitudinal positions, the cross-sectional areaand circumferential length at said second longitudinal position beingsmaller than the cross-sectional area and circumferential length at saidfirst longitudinal position, said piston comprising a container which iselastically deformable thereby providing for different cross-sectionalareas and circumferential lengths of the piston adapting the same tosaid different cross-sectional areas and different circumferentiallengths of the chamber during the relative movements of the pistonbetween the first and second longitudinal positions through saidintermediate longitudinal positions of the chamber, wherein the pistonis produced to have a production-size of the container in thestress-free and undeformed state thereof in which the circumferentiallength of the piston is approximately equivalent to the circumferentiallength of said chamber at said second longitudinal position, thecontainer being expandable from its production size in a directiontransversely with respect to the longitudinal direction of the chamberthereby providing for an expansion of the piston from the productionsize thereof during the relative movements of the piston from saidsecond longitudinal position to said first longitudinal position, thepiston comprising an enclosed space communicating with the deformablecontainer, the enclosed space having a variable volume, the containercontaining a deformable material and the enclosed space comprising aspring-biased pressure tuning piston, wherein a foot of the chambercomprises at least one valve and the valve has a core pin biased by aspring, said core pin moving towards the chamber when closing the valve.15. A piston-chamber combination comprising an elongate chamber which isbounded by an inner chamber wall, and comprising a piston in saidchamber to be sealingly movable relative to said chamber wall at leastbetween a first longitudinal position and a second longitudinal positionof the chamber, said chamber having cross-sections of differentcross-sectional areas and different circumferential lengths at the firstand second longitudinal positions, and at least substantiallycontinuously different cross-sectional areas and circumferential lengthsat intermediate longitudinal positions between the first and secondlongitudinal positions, the cross-sectional area and circumferentiallength at said second longitudinal position being smaller than thecross-sectional area and circumferential length at said firstlongitudinal position, said piston comprising a container which iselastically deformable thereby providing for different cross-sectionalareas and circumferential lengths of the piston adapting the same tosaid different cross-sectional areas and different circumferentiallengths of the chamber during the relative movements of the pistonbetween the first and second longitudinal positions through saidintermediate longitudinal positions of the chamber, wherein the pistonis produced to have a production-size of the container in thestress-free and undeformed state thereof in which the circumferentiallength of the piston is approximately equivalent to the circumferentiallength of said chamber at said second longitudinal position, thecontainer being expandable from its production size in a directiontransversely with respect to the longitudinal direction of the chamberthereby providing for an expansion of the piston from the productionsize thereof during the relative movements of the piston from saidsecond longitudinal position to said first longitudinal position, thepiston comprising an enclosed space communicating with the deformablecontainer, the enclosed space having a variable volume, the containercontaining a deformable material and the enclosed space comprising aspring-biased pressure tuning piston, wherein the piston includes atleast one valve and the valve is an inflation valve with a core pinbiased by a spring, the core pin of the valve being connected to a valveactuator or an activating pin.
 16. A combination according to claim 15,wherein the valve actuator for operating with at least one valve has aspring-force operated valve core pin, comprising a housing to beconnected to a pressure medium source; within the housing a couplingsection for receiving the valve to be actuated, a cylindercircumferentially surrounded by a cylinder wall of a predeterminedcylinder wall diameter and having a first cylinder end and a secondcylinder end which is farther away from the coupling section than saidfirst cylinder end and is connected to the housing for receivingpressure medium from said pressure source, a piston which is movablylocated in the cylinder and fixedly coupled to an activating pin forengaging with the spring-force operated valve core pin of the valvereceived in the coupling section, and a conducting channel between saidsecond cylinder end and said coupling section for conducting pressuremedium from said second cylinder end to the coupling section when thepiston is moved into a first piston position in which the piston is at afirst predetermined distance from said first cylinder end, saidconduction of pressure medium between said second cylinder end and thecoupling section being inhibited when the piston is moved into a secondpiston position in which the piston is at a second predetermineddistance from said first cylinder end which second distance being largerthan said first distance, wherein the conducting channel is arranged insaid cylinder wall and has a channel portion which opens into thecylinder at a cylinder wall portion having said predetermined cylinderwall diameter, and the piston comprises a piston ring with a sealingedge which sealingly fits with said cylinder wall portion, said sealingedge of the piston ring being located between said channel portion andsaid second cylinder end in said second piston position, therebyinhibiting said conduction of the pressure medium from said secondcylinder end into the channel in said second piston position, and beinglocated between said channel portion and said first cylinder end in saidfirst piston position, thereby opening the channel to said secondcylinder end in said first piston position.
 17. A combination accordingto claim 16, wherein a spring-force operated cap which closes thechannel above the valve actuator when the pressure comes above a certainpre-determined pressure value.
 18. A combination according to claim 16,wherein the channel can be opened or closed, the channel connects thechamber and the space between the valve actuator and the core pin, apiston is movable between an opening position and a closing position ofsaid channel, and the movement of the piston is controlled by anactuator which is steered as a result of a measurement of the pressurein the piston.
 19. A combination according to claim 16, wherein thechannel can be opened or closed, which connects the chamber and thespace between the valve actuator and the core pin.
 20. A combinationaccording to claim 16, wherein the piston is movable between an openingposition and a closing position of said channel.
 21. A combinationaccording to claim 20, wherein the piston is operated by a operatorcontrolled pedal, which is turning around an axle from a inactiveposition to an activated position and vice versa.
 22. A combinationaccording to claim 20, wherein the piston is controlled by an actuatorwhich is steered as a result of a measurement of the pressure in thepiston.
 23. A piston-chamber combination comprising an elongate chamberwhich is bounded by an inner chamber wall, and comprising a piston insaid chamber to be sealingly movable relative to said chamber wall atleast between a first longitudinal position and a second longitudinalposition of the chamber, said chamber having cross-sections of differentcross-sectional areas and different circumferential lengths at the firstand second longitudinal positions, and at least substantiallycontinuously different cross-sectional areas and circumferential lengthsat intermediate longitudinal positions between the first and secondlongitudinal positions, the cross-sectional area and circumferentiallength at said second longitudinal position being smaller than thecross-sectional area and circumferential length at said firstlongitudinal position, said piston comprising a container which iselastically deformable thereby providing for different cross-sectionalareas and circumferential lengths of the piston adapting the same tosaid different cross-sectional areas and different circumferentiallengths of the chamber during the relative movements of the pistonbetween the first and second longitudinal positions through saidintermediate longitudinal positions of the chamber, wherein the pistonis produced to have a production-size of the container in thestress-free and undeformed state thereof in which the circumferentiallength of the piston is approximately equivalent to the circumferentiallength of said chamber at said second longitudinal position, thecontainer being expandable from its production size in a directiontransversely with respect to the longitudinal direction of the chamberthereby providing for an expansion of the piston from the productionsize thereof during the relative movements of the piston from saidsecond longitudinal position to said first longitudinal position,wherein the piston includes at least one valve and the piston comprisingmeans to obtain a pre-determined pressure level.
 24. A piston-chambercombination comprising an elongate chamber which is bounded by an innerchamber wall, and comprising a piston in said chamber to be sealinglymovable relative to said chamber wall at least between a firstlongitudinal position and a second longitudinal position of the chamber,said chamber having cross-sections of different cross-sectional areasand different circumferential lengths at the first and secondlongitudinal positions, and at least substantially continuouslydifferent cross-sectional areas and circumferential lengths atintermediate longitudinal positions between the first and secondlongitudinal positions, the cross-sectional area and circumferentiallength at said second longitudinal position being smaller than thecross-sectional area and circumferential length at said firstlongitudinal position, said piston comprising a container which iselastically deformable thereby providing for different cross-sectionalareas and circumferential lengths of the piston adapting the same tosaid different cross-sectional areas and different circumferentiallengths of the chamber during the relative movements of the pistonbetween the first and second longitudinal positions through saidintermediate longitudinal positions of the chamber, wherein the pistonis produced to have a production-size of the container in thestress-free and undeformed state thereof in which the circumferentiallength of the piston is approximately equivalent to the circumferentiallength of said chamber at said second longitudinal position, thecontainer being expandable from its production size in a directiontransversely with respect to the longitudinal direction of the chamberthereby providing for an expansion of the piston from the productionsize thereof during the relative movements of the piston from saidsecond longitudinal position to said first longitudinal position,wherein the container contains a deformable material and the pistoncomprises an enclosed space communicating with the deformable container,the enclosed space having a variable volume, and the combination furthercomprising means for defining the volume of the enclosed space so thatthe pressure of fluid in the enclosed space relates to the pressureacting on the piston during the stroke.
 25. A piston-chamber combinationcomprising an elongate chamber which is bounded by an inner chamberwall, and comprising a piston in said chamber to be sealingly movablerelative to said chamber wall at least between a first longitudinalposition and a second longitudinal position of the chamber, said chamberhaving cross-sections of different cross-sectional areas and differentcircumferential lengths at the first and second longitudinal positions,and at least substantially continuously different cross-sectional areasand circumferential lengths at intermediate longitudinal positionsbetween the first and second longitudinal positions, the cross-sectionalarea and circumferential length at said second longitudinal positionbeing smaller than the cross-sectional area and circumferential lengthat said first longitudinal position, said piston comprising a containerwhich is elastically deformable thereby providing for differentcross-sectional areas and circumferential lengths of the piston adaptingthe same to said different cross-sectional areas and differentcircumferential lengths of the chamber during the relative movements ofthe piston between the first and second longitudinal positions throughsaid intermediate longitudinal positions of the chamber, wherein thepiston is produced to have a production-size of the container in thestress-free and undeformed state thereof in which the circumferentiallength of the piston is approximately equivalent to the circumferentiallength of said chamber at said second longitudinal position, thecontainer being expandable from its production size in a directiontransversely with respect to the longitudinal direction of the chamberthereby providing for an expansion of the piston from the productionsize thereof during the relative movements of the piston from saidsecond longitudinal position to said first longitudinal position,wherein the container contains a deformable material and comprises anelastically deformable material comprising reinforcement means.
 26. Acombination according to claim 25, wherein the reinforcement means arewindings having a braid angle which is different from 54°44′.
 27. Acombination according to claim 25, wherein the reinforcement meanscomprise a textile reinforcement.
 28. A combination according to claim25, wherein the reinforcement means comprise fibres.
 29. A combinationaccording to claim 28, wherein the fibers are arranged as to the TrellisEffect.
 30. A combination according to claim 25, wherein thereinforcement means comprises a flexible material positioned in thecontainer, comprising a plurality of at least substantially elasticsupport members rotatably fastened to a common member, the commonmembers connected to the skin of the container.
 31. A combinationaccording to claim 30, wherein said members and/or the common member areinflatable.
 32. A combination according to claim 25, wherein a foam orfluid is adapted to provide, within the container, a pressure higherthan the highest pressure of the surrounding atmosphere duringtranslation of the piston from the second longitudinal position of thechamber to the first longitudinal position thereof or vice versa.
 33. Apiston-chamber combination comprising an elongate chamber bounded by aninner chamber wall and comprising a piston in the chamber to besealingly movable in the chamber, the piston being movable in thechamber at least from a first longitudinal position thereof to a secondlongitudinal position thereof, the chamber comprising an elasticallydeformable inner wall along at least part of the length of the chamberwall between the first and second longitudinal positions, the chamberhaving, at the first longitudinal position thereof when the piston ispositioned at that position, a first cross-sectional area, which islarger than a second cross-sectional area at the second longitudinalposition of the chamber when the piston is positioned at that position,the change in cross-sections of the chamber being at least substantiallycontinuous between the first and second longitudinal positions when thepiston is moved between the first and second longitudinal positions thepiston including an elastically expandable container having changeablegeometrical shapes which adapts to the chamber inner wall during thepiston stroke thereby enabling a continuous sealing, and the elasticallyexpandable container having a stress free circumferential length equalto a circumferential length of the inner wall at the second longitudinalposition of the chamber.
 34. A combination according to claim 33,wherein the piston is made of an at least substantially incompressiblematerial.
 35. A combination according to claim 33, wherein the pistonhas, in a cross section along the longitudinal axis, a shape tapering ina direction from the first longitudinal position of the chamber to thesecond longitudinal position thereof.
 36. A combination according toclaim 35, wherein the angle (v) between the wall and the central axis ofthe cylinder is at least smaller than the angle (u) between the wall ofthe taper of the piston and the central axis of the chamber.
 37. Acombination according to claim 33, wherein the chamber comprises: anouter supporting structure enclosing the inner wall and a fluid held bya space defined by the outer supporting structure and the inner wall.38. A combination according to claim 37, wherein the space defined bythe outer structure and the inner wall is inflatable.
 39. A combinationaccording to claim 33, wherein the piston comprises an elasticallydeformable container comprising a deformable material.
 40. A pump forpumping a fluid, the pump comprising: a combination according to claim33, including, means for engaging the piston from a position outside thechamber, a fluid entrance connected to the chamber and comprising avalve means, and a fluid exit connected to the chamber.
 41. A pumpaccording to claim 40, wherein the engaging means have an outer positionwhere the piston is at the first longitudinal position of the chamber,and an inner position where the piston is at the second longitudinalposition of the chamber.
 42. A pump according to claim 40, wherein theengaging means have an outer position where the piston is at the secondlongitudinal position of the chamber, and an inner position where thepiston is at the first longitudinal position of the chamber.
 43. Apiston-chamber combination comprising an elongate chamber which isbounded by an inner chamber wall, and comprising a piston in saidchamber to be sealingly movable relative to said chamber wall at leastbetween a first longitudinal position and a second longitudinal positionof the chamber, said chamber having cross-sections of differentcross-sectional areas and different circumferential lengths at the firstand second longitudinal positions, and at least substantiallycontinuously different cross-sectional areas and circumferential lengthsat intermediate longitudinal positions between the first and secondlongitudinal positions, the cross-sectional area and circumferentiallength at said second longitudinal position being smaller than thecross-sectional area and circumferential length at said firstlongitudinal position, said piston comprising a container which iselastically deformable thereby providing for different cross-sectionalareas and circumferential lengths of the piston adapting the same tosaid different cross-sectional areas and different circumferentiallengths of the chamber during the relative movements of the pistonbetween the first and second longitudinal positions through saidintermediate longitudinal positions of the chamber, wherein the pistonis produced to have a production-size of the container in thestress-free and undeformed state thereof in which the circumferentiallength of the piston is approximately equivalent to the circumferentiallength of said chamber at said second longitudinal position, thecontainer being expandable from its production size in a directiontransversely with respect to the longitudinal direction of the chamberthereby providing for an expansion of the piston from the productionsize thereof during the relative movements of the piston from saidsecond longitudinal position to said first longitudinal position, meansfor engaging the piston from a position outside the chamber, means forintroducing fluid into the chamber in order to displace the pistonbetween the first and the second longitudinal positions of the chamber,and wherein the introducing means are adapted to introduce a combustiblefluid, such as gasoline or diesel, into the chamber, and wherein theactuator further comprises means for combusting the combustible fluid.